Ladders are essential articles in daily life and engineering industry. Some of ladders have long length so that it is inconvenient for carrying and storing them. In view of this, a conventional retractable ladder has been developed in the prior art. In general, this retractable ladder extends to its greater length at deployed position in use and retracts to its shorter length at its retracted or stowed position so as to be easily and conveniently carried and stored and thus become popular.
In one embodiment of the prior art, such a retractable ladder is provided with a pedal actuated device for descending the ladder sections. The pedal actuated device is disposed at the lowest rung member on a connecting rod which is movable at inside of the ladder stile of the rung member. The connecting rod is connected with a transmission means, which is disposed in a box of the lowest rung member of the ladder rung member, via a steel wire. The trailing end of the transmission means has an approximately U-shape transmission piece of which one end is shaped to move along with the connecting rod. The device for descending ladder sections comprises a foot pedal, a pulling rod and ropes. The rung box comprises a box, a manipulating hook, a guide bracket, a catch plate, a connecting rod, a transmission pin, a pin base, a transmission piece and the like.
It is apparent from the above that the device has a complicated structure, thereby resulting in a high cost and difficulty in assembling and maintenance.